Manufacture of low odor solvents



Aug. 1l, 1959 R. A. FINDLAY l MANUFACTURE OF LOW ODOR SOLVENTS Filed Aug. 16, 1957 ovm.

INVENTOR. R A FI NDL AY 2,899,311 Patented Aug. 11, 1959 2,899,3i7 MANUFACTURE oF Low oDoR soLvEN'rs Robert A. Findlay, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Application August 16, 1957, Serial No. 678,684

9 Claims. (Cl. 208-62) This invention relates to the manufacture of low odor solvents. In one aspect, the invention relates to a method for preparing highly parailinic solvents of low odor from a naphtha. In another aspect, the invention relates to an integrated sequence of steps whereby an extremely low odor and highly paratiinic hydrocarbon solvent is prepared employing a series of carefully controlled and interrelated treatment and purification steps.

The dry-cleaning, insecticide, printers ink, and painting industries have long desired odorless solvents. For many years, straight run naphthas deodorized by treatment with strong sulfuric acid and caustic had been the most nearly odorless materials obtainable. These deodorized naphthas still had much odor and frequently lacked desired solvent power.

It is, therefore, an object of the present invention to prepare highly paratinic solvents of low odor from naphtha streams containing in addition to the parains, naphthenes and other undesired hydrocarbons, as well as small amounts of non-hydrocarbon impurities. Other objects, as well as aspects and advantages of this invention will become apparent to those skilled in the art from a study of the accompanying disclosure and drawing.

According to the invention, therefore, there is provided a process wherein a naphtha feed is subjected to an integrated series of interrelated, carefully controlled processing steps to produce a solvent naphtha of W odor having a minimum of 99 weight percent parains and substantially no olefins or aromatics.

Preferably, the naphtha feed boils in the range from 250 to 450 F. and contains 35 to 95 weight percent parafns, 3 to 60 Weight percent naphthenes, not `more than 1 weight percent olenic materials, not more than weight percent aromatics, and small amounts of polar compounds, usually sulfur compounds. The solvent naphthaV producedaccording to the invention employing the preferred feed naphtha vis processed to produce aV solvent naphtha of low odor in the range of Z50-to 450 F.

The invention will be better understood from a study of the following discussion of the accompanying drawing which is a diagrammatic illustration of a process according to the invention. 1

Referring to the drawing, the feed hydrocarbon enters the system from line 1 and is a hydrocarbon naphtha, preferably containing 35 to 95 weight percent paraflins, 3 to 60 weight percent naphthenes, not more than l weight percent olenic materials, and not more than 25 weight percent aromatics, and usually has a boiling range from 250 to 450 F., preferably in the range from 300.

polar compounds, including sulfur compounds, which contribute to the odor of the naphtha feed. The reforming reaction is preferably effected at a temperature in the range from 600 to 1000 F., a pressure from 50 to 1000 p.s.i.g., a space velocity of 0.5 to 10 volumes/ volume/hour, usually in the presence of a catalyst, as is understood in the art. Examples of useful catalysts include platinum catalysts such as platinum on silicaalumina as described in U.S. Patent 2,479,109; another applicable catalyst is a cobalt-molybdate type catalyst supported on alumina, silica-alumina, clays, or other adsorbent carriers. The reforming reaction results in a product containing a maximum of 2 weight percent naphthenes and a maximum of 1 weight percent olens.

The reforming product ilows through line 6 to separation Zone 7 where the product is fractionated. The lightest stream contains hydrogen and H28 and flows through line 8. Preferably, this stream in line S is split two ways, valves 9 and 10 in lines 11 and 12, respectively, being open, 'while valve 4 is closed. The portion of the stream flowing through line 11 and line 5 to reforming zone 3 is sucient to supply the required amount of hydrogen in the reforming zone, as hereinbefore set forth. The other portion of the stream flows through line 12 to hydrogenation reactor 13. In separation Zone 7 there is preferably, although not necessarily, also fractionated from the reforming product a C5 and lighter hydrocarbon -cut which is withdrawn through line 14. The balance of the reformate flows through line 15 to solvent extraction zone 16. A polar selective solvent enters the Zone near the top through line 17, and extract is withdrawn through line 18 at the bottom. The solvent is any polar selective solvent which preferentially absorbs aromatics in preference to paraffin hydrocarbons. Examples of suitable selective solvents include diethylene glycol, triethylene glycol, dipropylene glycol, furfural, ,-dichloroethyl ether, and phenol. In any case, the extract, containing substantially all of the aromatics introduced with the feed in line 15, flows to stripper 19, where the solvent and extract are separated. The extract flows through line 20, valve 21, and line 22 to any desired further utilization. A portion of the extract can be recycled through line 23 and valve 24 as reflux to the solvent extraction Zone 16. The denuded or lean solvent Hows from stripper 19 through lines 25 and 17 to solvent extraction zone 16. The overhead from solvent extraction zone 16 is the raffinate phase, and it flows through line 26. From the bottom of accumulator 27 a portion of the raffinate phase can be recycled through line 28 with the solvent in line 17. The net remaining raiinate ows through lines 29 and 12 to hydrogenation reactor 13. The operation in solvent extraction zone 16 results in an eiiluent in line 29 which is a parainic rainate containing a maximum of 0.5 weight percent aromatics and a maximum of 1 weight percent naphthenes.

Preferably, enough hydrogen is added to reactor 13 to provide from 1 to 1.5 cubic feet of hydrogen at standard conditions for each gallon of the raffinate charged to the reactor. When this requires the addition of an excess of hydrogen over that already contm'ned in line 12, such make-up amounts can be added at any suitable point, such as to line 12 through line 30 and valve 31. On the other hand, if a surplus of hydrogen exists in line 12 a portion of the stream ilo-wing in line 12 can be withdrawn through line 30 and valve 31. The resulting mixture in hydrogenation reactor 13 is subjected to mild catalytic hydrogenation conditions, preferably at a temperature in the range from 30 to 90 F. with a residence time of 1 to 20 minutes. These conditions are chosen so that substantially all of the aromatics and olefins present are` destroyed and also so that any traces of nonhydrocarbon organic compounds, including organic sulfur,

nitrogen and oxygen compounds are destroyed by the hydrogenation treatment. The catalyst is added to reactor 13 through line 32. It is preferred that the hydrogen contain less than 0.05 weight percent 02 and less than 0.005 weight percent water. It is preferred that the reactor contain a stirred liquid phase of hydrocarbons containing a slurry of a hydrogenation catalyst as in the drawing, although a fixed bed catalyst method of hydrogenation can be employed. Examples of suitable hydrogenation catalysts include Raney nickel, nickel on kieselguhr, and nickel on alumina, tungsten sulfide on aruminum oxide, and copper chromite.

The hydrogenation reaction mixture is withdrawn through line 33 to settler 34. The spent hydrogen and any other gases are vented from settler 34 through line 35, while the settled spent catalyst is removed through line 36 and valve 37. The deeanted liquid hydrogenation product is withdrawn through line 38 to one of the adsorption zones, 39a and 39h. In this instance, valve 41 is open and the hydrogenation product flows through line 40 into absorber 39a. Valves 42 `and 43 are closed, as is valve 47 in line 48. In adsorber 39a the liquid hydrogenation eiuent is contacted with a mass of solid adsorbent such as silica gel which removes traces of polar compounds, aromatics, and oleiins, so that the product withdrawn from adsorber 39a through line 45 and valve 46 contains a minimum of 99 percent parafiins, no more than l percent naphthenes and only minimum traces of olefins and aromatics.

The adsorbers 39a and 39b are operated in the cycliccontinuous manner. Thus, hydrogenation product from settler 34 iiows continuously, the eiuent flowing in line 38 being cyclically switched from flow to one adsorber to the other. Thus, after a cycle of adsorption in 39a, valves 42, 43 and 47 are opened and Valves 41 and 46 are closed. rfhe effluent in line 38 thus ilows into adsorber 39h, through the adsorbent bed therein, and then through line 49 into line 53, valve 50 also being open. Valve 52 in line 51 is closed. The effluent in line 45 or in line 49 iiows via line 53 to fractionator 55 where a small amount of light ends are removed from the low odor solvent product.

While the one adsorber is in operation for treating efuent from settler 34, the other adsorber is being regenerated by desorbing adsorbed components therefrom with a heated hydrocarbon desorbent of considerably lower boiling point than the boiling range of the desired naphtha feed. Thus, desorbent, such as a pentane, is introduced into line 56 through valve 57 and flows through line 58 and valve 43 into and through adsorber 39a, withdrawn through line 48 and valve 47 to line 60. The desorbent in 60 contains some of the solvent product occluded in the solvent bed and is, therefore, recycled through the process via fractionation zone 61 and line 62. The desorbent and other materials lower boiling than the feed entering line 1 are fractionated overhead via line 63, and are thus removed from the system. In this manner even the occluded product is eventually recovered in the process.

An alternate method of providing the desorbent hydrocarbon is to close valve 57 and open valve 65a or 65b, respectively, valve 66 being closed. Thus the hydrocarbon cut in line 14 becomes the desorbent. The desorbent flows through the adsorber, then on to regeneration previously described.

In a specific example of the invention according to the process described with respect to the drawing, the feed is a naphtha boiling in the range from 300 to 400 F. and the reforming reaction is effected in the presence of a platinum on silica-alumina reforming catalyst. The approximate composition of the feed naphtha is as follows: paraiiins 52%, naphthenes 40%, aromatics 8%, and a trace of olefins, all percentages being by weight. The catalytic reforming reaction is effected at a temperature of about 825 F. and a pressure of about 500 p.s.i.g. and

a space velocity of 3 volumes/volume/hour. Hydrogen is also supplied to the reforming zone in the ratio of about 50 s.c.f. (60 F., 14.7 p.i.s.a.) of hydrogen for each gallon of the naphtha feed. The liquid product from the reforming step is of the approximate composition: parafiin 50 weight percent, naphthenes 2 weight percent, aromatics 47 weight percent, and olens 1 weight percent. After removal of all C5 and lighter hydrocarbons, the reforming product is subjected to countercurrent solvent extraction with diethylene glycol at approximately l00 F. The solvent extraction removes almost all of the aromatics and part of the naphthenes. The ratiinate is then subjected to hydrogenation in a stirred reactor with a nickel on kieselguhr hydrogenation catalyst slurried with the charge. In the hydrogenation reaction, hydrogen is added in an amount to provide 1.5 cubic feet of hydrogen at standard conditions for each gallon of hydrocarbon feed. The hydrogenation temperature is maintained at about 50 F., and the reaction is effected for a period of about 10 minutes. After separation of the hydrogenation product from the catalyst and removal of gases therefrom the hydrogenation product is passed through a xed bed of silica gel to adsorb traces of undesired components. The space velocity in this treatment is about 1.5 volumes/volume/hour, and the ternperature is maintained at about F. The treated product is then fractionated to remove materials boiling outside the boiling range of the feed naphtha, and there is thereby obtained a paraftinic solvent naphtha of very low odor and consisting of more than 99 weight percent parains and containing substantially no olefins or aromatics.

In the process described, there is sometimes obtained a small amount of solvent dissolved in the raffinate in accumulator 27. In lsuch cases this solvent can be removed from the raitinate in line 29 by distillation or by other suitable means before the raffinate is passed through line 12 into reactor 13.

As will be evident to those skilled in the art, various modifications of this invention can be made or followed in the light of the foregoing disclosure and discussion without departing from the spirit and scope of the disclosure or from the scope of the claims. For instance, in the process described, stream 8 or stream 12 can be treated for the removal of HZS, as by caustic washing, before passing the streams to further utilization as described with respect to the figure.

I claim:

1. An integrated process for preparing a low odor parafiinic solvent comprising the steps in combination and in sequence, as follows: catalytically reforming in a reforming zone a naphtha feed boiling in the range from 250 to 450 F. and containing 35 to 95 weight percent parafrins, 3 to 60 weight percent naphthenes, not more than 1 percent oleiinic materials, not more than 25 weight percent aromatics, and small amounts of polar compounds including sulfur compounds, said reforming being effected at a temperature in the range from 600 to 1000 F., 50 to 1000 p.s.i.g. and at a space velocity of 0.5 to 10 volumes/volume/hour, and forming a product of said reforming containing a maximum of 2 weight percent naphthenes and a maximum of 1 weight percent olefins; distilling said reforming product to produce a rst stream containing hydrogen and H28 produced in the reforming step, a second stream containing the C5 and lighter hydrocarbons, and a third stream containing the balance of said reforming product; subjecting said third stream to a solvent extraction step with a polar selective solvent, removing as extract product a stream containing substantially all of the aromatics and a paraiiinic rainate containing a maximum of 0.5 weight percent aromatics and 1 weight percent naphthenes;

. splitting said first stream into a fourth and fifth stream,

recycling said fourth stream to said reforming zone in an amount necessary to supply from 20 to 200 standard cubic feet of hydrogen tor each gallon of said naphthal feedj'mixing said fifth stream with said raflinate in a ratiol to provide 1 to 1.5' cubic feet of hydrogen at standard conditions for cach gallon of said raflnate; subjecting the resulting mixture tomild hydrogenation conditions in the presence of a hydrogenation catalyst at a temperature in the range from 30 to 90 F. and a residence time of 1 to 20 minutes, said conditions being effective to destroy substantially all of the aromatics and olens present and also being effective to destroy traces of non-hydrocarbon organic compounds including organic sulfur, nitrogen and oxygen compounds; `separating the hydrogenation product from'said hydrogenation catalyst and removing normallygaseous materials therefrom; vtreating the resulting naphtha with a porous adsorbent selective for polar compounds and thereby removing traces of sulfur, nitrogen and oxygen compounds, oletins and aromatics; and recovering a solvent naphtha of low odor boiling in the range from 250 to 450 F. and having a minimum of 99 Weight percent paraiins and substantially no olefins or aromatics.

2. An integrated process for preparing a low Vodor paraffnic solvent comprising the steps in combination and in sequence, as follows: catalytically reforming in a reforming zone a naphtha feed boiling in the range from 250 to 450 F. and containing 35 to V95 Weight percent parains, 3 to 60 weight percent naphthenes, not more than 1 percent olenic materials, not more than 25 weight percent aromatics, and small amounts of polar compounds including sulfur compounds, said reforming being effected at a temperature in the range from 600 to 1000 F., 50 to 1000 p.s.i.g. and at a space velocity of 0.5 to volumes/volume/hour, and forming a p-roduct of said reforming containing a maximum of 2 weight percent naphthenes and a maximum of 1 weight percent olens; distilling said reforming product to produce a first stream containing hydrogen and H28, produced in the reforming step, a second stream containing the C5 and lighter hydrocarbons, and a third stream containing the balance of said reforming products; subjecting said third stream to a solvent extraction step with a polar selective, solvent, removing as extract product a stream containing substantially all of the aromatics and a parafiinic raffinate containing a maximum of 0.5 Weight percent aromatics and 1` weight percent naphthenes; splitting said first stream into a fourth and fth stream, recycling said fourth stream to said reforming zone in an amount necessary to supply from 20 to 200 standard cubic feet of hydrogen for each gallon of said naphtha feed; mixing said lifth stream with said ralinate in a ratio to provide 1 to 1.5 cubic lfeet of hydrogen at standard conditions for each gallon of said ranate; subjecting the resulting mixture to mild hydrogenation conditions in the presence of hydrogenation catalyst at a temperature in the range from 30 to 90 F. and a residence time of 1 to 20 minutes, said conditions being effective to destroy substantially all of the aromatics and olelins present and also being effective to destroy traces of nonhydrocarbon organic compounds including organic sulfur, nitrogen and oxygen compounds; separating the hydrogenation product from said hydrogenation catalyst and removing normally gaseous materials therefrom; treating the resulting naphtha with a porous adsorbent selective for polar compounds and thereby removing traces of sulfur, nitrogen and oxygen compounds, olens and aromatics; and recovering a solvent naphtha of low odor boiling in the range from 250 to 450 F. and having a minimum of 99 weight percent paraflins and substantially no olens or aromatics, said treating with said adsorbent being eiected by cyclically passing through one and then another of a pair of beds of said adsorbent, while regenerating the other said bed not being used as adsorbent by passing a hot hydrocarbon desorbent through said bed, said hydrocarbon being lower boiling than said naphtha feed, removing said lower boiling hydrocarbon containing components re moved from said bed, distilling said removed desorbent stream into a rst cut boiling in the range of said naphtha feed `andfa second cut lower boilingl than said naphtha feed, vand combining saidirst cut with said naphtha feed before reforming same in said reforming zone.

"3. kAl process of claim 2 wherein said desorbent comprises said second stream.

4. An integrated process for preparing a low odor paranic solvent comprising the steps in combination and in' sequence, as follows: catalytically reforming in a reforming zone a naphtha feed boiling in the range from`250 to 450 F. and containing 35 to 95 weight percent paraiiins, 3 to V60 weight percent'naphthenes, not more than 1 percent olenic materials,'not more than 25 weight percent aromatics, andl small amounts of polar compounds including sulfur compounds, inthe presence of 20 to 200 standard cubic feet of hydrogen for each gallon of said naphtha feed and thereby forming a product of said reforming containing a maximum of 2 weight percent naphthenes and a maximum of 1 weight percent oletins; removing from said reforming product a iirst stream containing hydrogen and HZS produced in the reforming step and a second stream containing the balance of said reforming product; subjecting at least a portion of said second stream to a solvent extraction step with a polar selective solvent, removing as extract product a stream containing substantially all of the aromatics and at least a portion of the naphthenes and therebyv'producing a parafiinic raiinate; passing at least a portion of said first stream into admixture with said raffinate; subjecting the resulting admixture to hydrogenation conditions in the presence of a hydrogenation catalyst and thereby destroying substantially all of the aromatics and oleiins present and traces of non-hydrocarbon organic compounds including sulfur, nitrogen and oxygen compounds; separating a resulting naphtha from said hydrogenation catalyst and treating said resulting naphtha with a porous adsorbent selective for polar compounds and thereby removing traces of sulfur, nitrogen and oxygen compounds, olens and aromatics; and recovering a solvent naphtha of low odor boiling inthe range from 250 to 450 F. land having a mini- -mum of 99 Weight percent parains and ysubstantially no olefins or aromatics.

5. An integrated process for preparing a low odor paraliinic solvent comprising the steps in combination and in sequence, as follows: catalytically reforming in a reforming zone a naphtha feed boiling in the range from 250 to 450 F. and containing 35 to 95 Weight percent paraftins, 3 to 60 weight percent naphthenes, not more than 1 percent olefnic materials, not more than 25 weight percent aromatics, and small amounts of polar compounds including sulfur compounds, in the presence of 20 to 200 standard cubic feet of hydrogen for each gallon of said naphtha-feed and thereby forming a product of said reforming containing a maximum of 2 weight percent naphthenes and a maximum of 1 Weight percent oletins; removing from said reforming product a first stream containing hydrogen and HZS produced in the reforming step and a second stream containing the balance of said reforming product; subjecting at least a portion of said second stream to a solvent extraction step with a polar selective solvent, removing as extract product a stream containing substantially all of the aromatics and at least a portion of the naphthenes and thereby producing a paranic ranate; passing at least a portion of said rst stream into admixture with said rainate; subjecting the resulting admixture to hydrogenation conditions in the presence of a hydrogenation catalyst and thereby destroying substantially all of the aromatics and olefins present and traces of nonhydrocarbon organic compounds including sulfur, nitrogen and oxygen compounds; separating a resulting naphtha from said hydrogenation catalyst and treatingsaid resulting naphtha with a porous adsorbent selective for polar compounds and thereby removing traces of sulfur, nitrogen and oxygen compounds, olefins and aromatics; and recovering a solvent naphtha of low odor boiling in the range from 250. to 450 F. and having a minimum of 9 9 weight percent paralns and substantially no olens or aromatics, said treating with. said adsorbent being elfected byV cyclically' passing through one and then another of a pair of beds of said adsorbent, while regenerating the other said bed not being used as adsorbent by passing a hot hydrocarbon desorbent through saidwbed, said hydrocarbon being lower boiling than said naphtha feed removing said lower boiling hydrocarbon containing components removed from said bed, distilling said removed desorbent stream into a first cut boiling in the range of said naphtha feed and a second cut lower boiling than said naphtha feed, and combining said first Vcut with said naphtha feed before reforming same insaid reforming zone.

6. A process of claim wherein said desorbent comprises a stream formed by removing C5 and lighter hydrocarbons from said second stream before subjecting same to said solvent extraction step.

7. A process according to claim 1 wherein said naphtha feed boils in the range from 300 to 400 F.

8. An integrated process for preparing a low odor paratiinic solvent comprising the steps in combination and in sequence, asV follows: catalytically reforming in a reforming zone a naphtha feed containing naphthenes and boiling in the range of 250 to 450 F. in the pres,- ence of hydrogen and thereby forming a product of said reforming, said reforming being effected under condi tions resulting in the formation of aromatics from naphthenes and the conversion of polar compounds to gaseous forms; removing from said reforming product a rst stream containing hydrogen and H28 produced in the reforming step and a second stream containing the balance of said reforming product; subjecting at least a portion of said second stream to a solvent extraction step with a polar selective solvent, removing as extract product a stream containing substantially all of the aromatics and at least a portion of the naphthenes and thereby producing a paraflinic raffinate; passing hydrogen into admixture with said raffinate; subjecting the resulting admixture to hydrogenation conditions in the presence of a hydrogenation catalyst and thereby destroying 8 substantially all of the aromatics and olelns present and traces of non-hydrocarbon organic compounds; separating `aresulting naphthafrom said hydrogenation catalyst and treating said resulting naphtha with a porous adsorbent selective for polar compounds; `and recovering, a solvent naphtha of low odor having a .minimum of` 99 weight percent paratiins and substantially no olensl or aromatics.

9. An integrated process for preparing a low odor and boiling in the range of 250 to 450 F. in the presf enceof hydrogen and thereby forming a product of said reforming, said reforming being effected under conditions resulting in the formation of aromatics from naphthenes and the conversion of polar compounds to gaseous forms; removing from said reforming product a first stream containing hydrogen and H25 produced in the reforming step and a lsecond stream containing the balance of said reforming product; subjecting at least a portion of said second stream to a solvent extraction step with a polar selective solvent, removing as extract product a stream containing substantially all of the aromatics and at least a portion of the naphthenes and thereby producing a paratinic railinate; passing` hydrogen into admixture with said rainate; subjecting the resulting admixture to hydrogenation conditions in the presence of hydrogenation catalyst and thereby destroying substantially a-ll of the Aaromatics andolefins present and traces of non-hydrocarbon organic compounds;- separating fa result-ing naphtha from said hydrogenation catalyst and treating said resulting naphtha with a porous adsorbent selective for polar compounds; and recovering a solvent naphtha of low odor having a minimum of 9,9 weight percent paraliins and substantiallyV nov olefins or aromatics; desorbing adsorbate from said porous adsorbent, and returning at least a portion of said desorbed adsorbate to the catalytic reforming step in said reforming zone.

References Cited in the tile of this patent UNITED STATES PATENTS 2,522,696 Watson Sept. 19, 1950 2,740,751 Hfaensel et al. Apr. 3, 19.56 2,764,621 Fulton Sept. 25, 1956 2,775,627 Lavender Dec. 25, 1956 2,799,627 Haensel July 16, 1957 UNITED STATES PATENT oFFIcE CERTIFICATE 0F CORRECTION Patent Norb 2,899,377 August ll, 1959 Robert A. Findlay It is herebjr certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 60, rund column 5, line 33, for "volumes", each occur rence, read volume line 0, for "productsH read product line 42, after "selective" strike out the comme.; column '7, line `1.4, after "feed" insert a comme; column 8, line 29, for "of hydrogenaton" read -w of a hydrogenaton Signed end sealed this lst day of March 1960.,

(SEAL) Attest:

KARL Hm AXLINE ROBERT C. WATSON Attesting Ocer Commissioner of Patents 

1. AN INTEGRATED PROCESS FOR PREPARING A LOW ODOR PARAFFINIC SOLVENT COMPRISING THE STEPS IN COMBINATION AND IN SEQUENCE, AS FOLLOWS: CATALYTICALLY REFORMING IN A REFORMING ZONE A NAPHTHA FEED BOILING IN THE RANGE FROM 250 TO 450*F. AND CONTAINING 35 TO 95 WEIGHT PERCENT PARAFFINS, 3 TO 60 WEIGHT PERCENT NAPHTHENES, NOT MORE THAN 1 PERCENT OLEFINIC MATERIALS, NOT MORE THAN 25 WEIGHT PERCENT AROMATICS, AND SMALL AMOUNTS OF POLAR COMPOUNDS INCLUDING SULFUR COMPOUNDS, SAID REFORMING BEING EFFECTED AT A TEMPERATURE IN THE RANGE FROM 600 TO 1000*F., 50 TO 1000 P.S.I.G. AND AT A SPACE VELOCITY OF 0.5 TO 10 VOLUMES/VOLUME/HOUR, AND FORMING A PRODUCT OF SAID REFORMING CONTAINING A MAXIMUM OF 2 WEIGHT PERCENT NAPHTHENES AND A MAXIMUM OF 1 WEIGHT PERCENT OLEFINS; DISTILLING SAID REFORMING PRODUCT TO PRODUCE A FIRST STREAM CONTAINING HYDROGEN AND H2S PRODUCED IN THE REFORMING STEP, A SECOND STREAM CONTAINING THE C5 AND LIGHTER HYDROCARBONS, AND A THIRD STREAM CONTAINING THE BALANCE OF SAID REFORMING PRODUCT; SUBJECTING SAID THIRD STREAM TO A SOLVENT EXTRACTION STEP WITH A POLAR SELECTIVE SOLVENT, REMOVING AS EXTRACT PRODUCT A STREAM CONTAINING SUBSTANTIALLY ALL OF THE AROMATICS AND A PARAFFINIC RAFFINATE CONTAINING A MAXIMUM OF 0.5 WEIGHT PERCENT AROMATICS AND 1 WEIGHT PERCENT NAPHTHENES; SPLITTING SAID FIRST STREAM INTO A FOURTH AND FIFTH STREAM, RECYCLING SAID FOURTH STREAM TO SAID REFORMING ZONE IN AN AMOUNT NECESSARY TO SUPPLY FROM 20 TO 200 STANDARD CUBIC FEET OF HYDROGEN FOR EACH GALLON OF SAID NAPHTHA FEED; MIXING SAID FIFTH STREAM WITH SAID RAFFINATE IN A 